1. Field of the Invention
This invention relates to flow control valves. More particularly, it relates to a valve combining the control of flow direction at one end and the control of the flow rate at a second end.
2. Description of the Prior Art
In the prior art, U.S. Patent 3,363,650 describes a combination plug and check valve. A cylindrical plug member is located at one end of a valve and a check valve is located at the other end.
In U.S. Pat. No. 3,474,818, fluid flow is stopped in one direction in a check valve by a flapper plate and in the opposite direction, the flow fully opens the flapper plate. The valve permits flow in one direction and prevents fluid flow in the opposite direction.
In U.S. Pat. No. 3,851,665, there is a plug shut off and double check valve. A pair of tandem check valves are coaxially mounted in a plug which is lightly spring biased downwardly in a closed relationship with the valve seat.
In U.S. Pat. No. 4,846,221, a ball valve has a built-in check valve. A sealing contact portion of the check valve is brought into sealing contact with the valve seat by the biasing force of a spiral spring.
In U.S. Pat. No. 4,928,725, a combination plug and two way check valve is described. There are first and second valve seats in the body of the valve. The ball member is rotatably received in the body between the seats. A clapper is pivotally supported within the ball and is pivotable in a closed position blocking the passageway in an open position. The clapper is used as a direction flow control but is not controlled by a spring.
U.S. Pat. No. 5,373,868 describes a ball valve with a modular check valve assembly. A ball valve has a valve casing enclosing the ball and having a check valve within the ball.
Although all the above prior art references talk about valve structure having a control of flow, there is no inexpensive combination spring action flow direction and flow rate control disclosed. In the present invention a spring tension flapper valve provides an inexpensive method of controlling the direction of flow and a rotatable plug controls the rate of flow in a single polymeric housing.